Ana Maria Rey(JILA and Department of Physics, University of Colorado, Boulder, Colorado)

We study the behavior of few-electrons confined in a double-well
quantum dot
in semiconducting carbon nanotubes. These carbon nanostructures
exhibit
richer physics than GaAs ones due to the additional valley degree of
freedom. We calculate and characterize the low energy eigenstates
in the
presence of a magnetic field and double-well detuning. Spin-orbit
coupling
lifts the spin and valley degeneracy and, in the presence of
exchange
interactions, leads, at small detunings and weak magnetic fields,
to a
spin-valley antisymmetric two-electron ground state which is not
a pure
spin-singlet state. At large detuning, the strong Coulomb
interactions
accessible in carbon nanotubes can substantially modify the
non-interacting
eigenstates via higher orbital-level mixing. The latter manifest
in current
transport experiments by the disappearance of the Pauli blockade.

*This work was supported in part by NSF and NIST.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.C1.112